How to programmatically modify any files properties.

I am trying to traverse through a set of directories and then set the file properties, summary - title field. When you go to a file and right click on it and select properties, and the select the summary tab, you will see the Title field, plus a bunch of other fields like subject and author. All files have these regardless of what it is. I will be dealing with TIFF files and .TXT files. Does anyone know how to programmatically set these using C#? Thanks

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and as you notice my file is a TIF file. Unfortunately when you modify the properties for a TIF file as shown they do not show up in the Summary tab when you view them manually. Although if you go and read them programmatically you will see that the properties indeed were set. On further research apparently this is because graph files are not Ole compliant (whatever that means..).
If you do the above for a .TXT file it works fine, but if you do it for a .TIF or a JPEG file it doesn't work so well. You won't see it when you right click and view the properties, but you can retrieve (programmatically) the values that you set (again only programmatically). If you set the property values in a TIF file manually (using the summary tab etc. ) you can NOT access them programmatically, but this only applies to TIF files and JPEG files (and graphics files since they are not Ole compliant). I am still searching for a way to get at the true Author, Subject, Title properties of the graphics file. Any help is much appreciated.